Many different types of such tamperproof or transport protected reclosing devices are known. The majority of the known constructions are based on the concept, that the cover frame and the reclosing cover, when the container has not yet been broken open, are to be connected in such a way, that some part of the frame or the cover must be broken or smashed in order to open up the reclosing cover, or that some part of the cover must be cut or torn in order to gain access to the product in the container.
Thus, U.S. Pat. No. 3,966,080 describes a reclosing device, in which the cover frame and the reclosing cover are molded together in such a way, that the cover is connected to the frame along the hinged portion as well as along the opening edge of the cover, and the container is opened up by prying open or pressing down the cover in such a strong way, that the joint between the opening edge of the cover and the frame will be broken. Such a device is difficult and expensive to manufacture and often a relatively large force is required to open up the container by breaking the joint between the cover and the cover frame.
European patent No. 72,294 shows a reclosing device, which can be manufactured in a comparatively simple way by molding a plastic material, the cover element and the frame element being turned up in one single plane and the frame, in order to provide a tamperproof protection, being designed with projecting pins and the cover element with corresponding holes, and the reclosing cover, before putting on the cover on a container, being turned down above the frame in order to let the pins in the frame project upwards through said holes in the cover, subsequent to which the projecting parts of the frame pins are reshaped by means of heat in order to make them wider and able to lock the cover element against the frame element. The container can subsequently be opened up by breaking the pins or cutting them. The breaking of the widened parts of the pins can also create difficulties, and the locking of the cover against the frame requires an additional working moment, since the pins are to be shaped by heating.